This project will answer important questions regarding remediation of cognitive decline in older adults and address two critical areas of training: advanced imaging (magnetic resonance spectroscopy, functional connectivity) and cognitive/clinical aging interventions (cognitive training). The PI is a cognitive neuroscientist wth a strong background in transcranial direct current stimulation (tDCS), cognition, and electrophysiology, as well as a basic understanding of magnetic resonance imaging. The K01 will provide protected time and training to focus his research career firmly in cognitive aging, specifically focusing on the development of novel non- invasive treatments for age-related cognitive decline. This training will afford the knowledge required to translate his basic science expertise into clinical translational applications in aging populations. The current study will investigate a method for enhancing cognitive training effects in healthy older adults and improving functional transfer of skills by employing a combined intervention approach targeting facilitation of neural plasticity and optimal learning state. Adults over the age of 65 represent te fastest growing portion of the US population. As such, age-related cognitive decline represents a major concern for public health. Recent research suggests that cognitive training in older adults can have lasting effects on performance, lasting up to 10 years. However, these effects are typically limited to the tasks trained, with little transfer to other cognitive abilities or evryday skills. This study will examine the impact of pairing cognitive training with tDCS. Individual effects of tDCS and cognitive training on cognitive, functional, and neuroimaging measures will be assessed. tDCS is a non-invasive brain stimulation method that directly stimulates brain regions involved in active cognitive function and enhances neural plasticity when paired with a variety of cognitive tasks. We will compare changes in cognitive and brain function resulting from cognitive training and cognitive training combined with tDCS using a comprehensive neurocognitive, clinical, and multimodal neuroimaging assessment of brain structure, function, and metabolic state. Functional connectivity from functional magnetic resonance imaging (fMRI) will be used to assess the coherence of brain response during working memory and focused attention; the active cognitive abilities trained by cognitive training. Proton magnetic resonance spectroscopy (MRS) will assess cerebral metabolites, including GABA concentrations sensitive to neural plasticity in task-associated brain ROIs. We hypothesize that: 1) tDCS will enhance neurocognitive function, brain function, and functional improvements from cognitive training; 2) Effects of tDCS on cognitive training will be maintained up to 3 months following training; and 3) Neuroimaging biomarkers of cerebral metabolism, neural plasticity (GABA concentrations) and coherence of functional brain response (fMRI) in default network and functionally relevant brain regions will predict individual response to cognitive training and tDCS.